The present invention relates to a novel acrylic rubber composition as well as to a cured product or vulcanizate thereof. More particularly, the invention relates to an improved acrylic rubber composition having excellent workability in processing and vulcanization and capable of giving a vulcanized rubber article which is outstandingly free from the troubles due to sticking to the surface of a metallic body with which the rubber articles is kept in contact at an elevated temperature under pressure. Thus the compositions are useful as a material of rubber packings, gaskets, O-rings and the like used as automobile parts as compared with conventional acrylic rubber compositions.
As is known, acrylic rubbers have excellent heat resistance and oil resistance so that they are widely used as a material for rubber-made parts in automobiles. It is a trend in recent years that the applications of acrylic rubbers as a material of automobile parts such as, for example, packings, gaskets and O-rings of oil filters are rapidly expanding. Acrylic rubbers in general, however, are not without problems and disadvantages. One of the disadvantages in the acrylic rubbers is that the workability of acrylic rubber compositions is relatively poor because of the problem of heavy sticking to the surface of the milling rollers and other rubber-processing machines to cause a great decrease in the productivity. In addition, shaped and vulcanized articles of an acrylic rubber composition are also not free from the problem of sticking to the surface of a body with which the rubber article has been kept in contact at an elevated temperature under pressure as is the case with rubber packings, gaskets and O-rings so that a great difficulty is sometimes encountered in replacing rubber parts in automobile maintenance.